1. Field of the Invention
The present invention relates to tape measure apparatus, and more particularly to tape measures configured to easily and accurately measure distances from corner to corner, and further to fixtures for use in conjunction with tape measures providing an easy and accurate measurement from corner to corner.
2. Description Relative to the Prior Art
There are many inventions relating to carpenter's tape measures, and many varieties of these measures in common use.
Generally speaking, the carpenter's tape measure consists of a metal or plastic tape blade which is coiled around a drum located within a housing. The blade is generally terminated with an L-shaped end piece, with one leg of the L parallel to the blade end, and the other leg perpendicular to the blade end. The blade may be withdrawn from the housing by pulling the tape through an opening in the housing, and retracts back into the housing through the reverse of the withdrawal process. The L-shaped end piece serves the dual function of facilitating measurement of the work piece, and of preventing retraction of the tape blade entirely within the housing.
Practically all modern carpenter's tape measures contain locking mechanisms, through the use of which the tape may be locked in position while partially withdrawn from the housing.
As commonly used, a portion of the tape is pulled out of the housing, and the end piece aligned with one end of the work piece to be measured, while the tape extends over the length of the work and beyond.
When the tape measure is used to make internal corner-to-corner measurements, in a room, for example, many carpenters will place the end piece 2 against the far corner 4, extend the tape along the floor 6, and bend the blade of the tape into the near corner 8, as shown in FIG. 1.
The technique of FIG. 1 is does not provide a high degree of accuracy, however, because the tape will naturally assume a radius as it passes the near corner 8, and the user must estimate where the tape blade would intersect with the corner if it could be made to conform exactly with the corner. The tendency of the tape to form said radius is exacerbated in most commercially available tape blades which have a curved cross section to provide a degree of rigidity to the blade when extended without support.
Several techniques have been used to overcome this problem. The most common of these is to use the housing of the tape measure an extension of the tape blade, and to place the housing itself into the near corner 8 and resting on the floor 6, while extending the tape so that the end piece fits exactly into the far corner 4, as shown in FIG. 2. Thus, the length to be measured equals the length of the tape from the far corner 6 to the near end of the tape housing 10, plus the length of the tape housing itself.
This technique has the shortcoming that it is awkward to perform, since the user is required to kneel or squat down while so doing. As a result, many carpenters continue to use the technique shown in FIG. 1, despite its inherent inaccuracy.
The current invention allows for accurate corner to corner measurements without the drawbacks of the technique of FIG. 1.